Inu and I had a recent article in which we explained how NAFTA Chapter 20 state-state dispute settlement hasn't been working because of problems with appointing panelists (in large part because the roster of panelists was not filled). It doesn't look like this article made much of an impression on the negotiators, because the relevant provisions in the the new NAFTA trade deal, now in Chapter 31, look pretty much the same as what was in Chapter 20.
This is a real shame, and Congress should look at this closely. Presumably, most people in all three countries who pushed for particular obligations want those obligations to be enforceable. There needs to be a way to ensure that panels get appointed when needed.
Now, the problem noted above was the result of the U.S. blocking appointments, and maybe people in the U.S. assume that Canada and Mexico would never do such a thing. Regardless, if I were Congress, I would ask tough questions about how it can be guaranteed that panels will be appointed.
As for Canada and Mexico, who are most likely to be affected by this, I wonder if they got any assurances about how the U.S. would act in this regard.